How to Know You May be Ready for Knee Replacement Surgery
Knee replacement surgery is considered when all available, non-operative treatments for knee arthritis have been tried without relieving the patient’s knee pain or improving their mobility. Non-operative alternatives to knee replacement surgery include pain medications; activity modifications; anti-inflammatory medications; arthroscopic joint debridement; joint realignment; physical therapy; bracing, and joint injections. Total knee replacement surgery is considered when knee pain and loss of mobility are severely affecting the quality of a person’s life.
Make the decision with your surgeon
After your orthopedic evaluation, your surgeon will discuss alternatives with you. If x-rays show severe joint damage and no other means of treatment provides relief, total knee replacement may be recommended. Knee replacement is an elective procedure. If the pain becomes simply too much to bear, then, with your surgeon’s guidance, you’ll know when you are ready to consider knee replacement surgery.
Components for Replacement Surgery
Implant designs vary in important ways to meet specific patient needs. Restoration of normal knee joint function is the goal of knee replacement surgery.
Some implants are designed for patients undergoing total knee surgery for the first time. This is called “primary” knee replacement.
Other implants are designed specially for people undergoing a second operation, called “revision surgery.” This is where it becomes necessary to remove the primary implant and occurs in a small percentage of cases.
Another variable is whether the implant is cemented or cementless. Most knee implants are affixed using a special bone cement similar to dental cement. Certain implants have been approved by the FDA to be implanted without bone cement and are secured biologically as the patient’s tissues grow and attach to a special porous texture that coats the implant. These are called cementless. Both types have advantages in different patient situations that your surgeon will assess. In many cases, both types are used in combination.
The most common knee implant consists of a femoral (thigh) component, a tibial (shin) and bearing components; and a patella (kneecap):
The femoral, or thighbone, component is made of metal (chromium-cobalt) and covers the lower end of the thighbone. It may be cemented to the bone or, for some implants, inserted without cement so that the patient’s tissues grow into the porous coating of the device. This natural bond between the patient’s tissue and the implant is called “biological fixation.”
The tibia, or shin bone, component is often called a “tray” and is typically made of metal (titanium or chromium-cobalt), and a plastic cushion, or bearing. The tibial component may be secured with cement or by biological fixation. The metal forms the base of this component, while the plastic (ultra-high molecular weight polyethylene) is attached to the top of the metal to serve as a bearing. This bearing creates a smooth gliding surface between the metal of the thigh and shin components.
The patella, or knee cap, component is made of either of plastic (polyethylene), or of a combination of plastic and metal. Again, this component may be fixed with or without cement.
Knee Replacement Surgery
The steps involved in replacing the knee begin with making an incision on the front of the knee to allow access to the knee joint. There are several different approaches used to make the incision, usually based on the surgeon’s training and preferences.
Shaping the Distal Femoral Bone: Once the knee joint is entered, a special cutting jig is placed on the end of the femur. This jig is used to make sure that the bone is cut in the proper alignment to the leg’s original angles, even if the arthritis has made you bowlegged or knock-kneed. The jig is used to cut several pieces of bone from the distal femur so that the artificial knee can replace the worn surfaces with a metal surface.
Preparing the Tibial Bone: Attention is then turned toward the lower bone, the tibia. The top of the tibia is cut using another jig that ensures the alignment is satisfactory.
Preparing the Patella: The undersurface of the patella is removed.
Placing the Femoral Component: The metal femoral component is then placed on the femur. When using an uncemented femoral component, the prosthesis is held on the end of the bone through a taper on the end of the bone. In addition, the metal prosthesis is cut so that it matches the taper almost exactly. Driving the metal component onto the end of the bone holds the component in place by friction. The stable implant will allow bone tissue to grow into the porous surface, providing long-term stability. With a cemented femoral component, an epoxy cement is used to attach the metal prosthesis to the bone.
Placing the Tibial Components: The metal tray that will hold the polyethylene spacer is attached to the top of the tibia. The metal tray is either cemented into place, or may be held with screws if the component is uncemented. The screws are primarily used to hold the tibial tray in place until the bone grows into the porous coating. (The screws remain in place and are not removed.)
The plastic spacer is then attached to the metal tray of the tibial component. If this component wears out while the rest of the artificial knee is sound, it can be replaced.
Placing the Patellar Component: The patella button is usually cemented into place behind the patella.
Closing the Incision: There are several ways that orthopedic surgeons can close the incision after performing an artificial joint replacement. Stainless steel staples are popular with many orthopedic surgeons because they are easy to put in and easy to take out. This can reduce time in the operating room. The stainless-steel staples are one of the most inert types of sutures, meaning they have a very low risk of allergic reaction by the patient.
Some surgeons prefer using sutures that dissolve on their own after several weeks. These stitches are normally put in just under the skin. The advantage of this type of closure is that you don’t have to have your stitches taken out! Usually there are special tape closures (sometimes called “butterfly” tapes or “steri-strips”) that are used to hold the edges of the skin closed for the first few days. If you see strips of tape across the incision, this is probably the type of closure that was done. This type of incision closure takes a bit more time in the operating room. There is also a small chance that you may have an allergic reaction to the stitch material that delays the healing of the incision, but this risk is pretty small.
Finally, many surgeons still use the old “tried and true” nylon stitches one at a time. Nylon has withstood the test of time and is nearly as inert as stainless steel. It is strong and holds well until it is removed (somewhere between 10 to 14 days after surgery).
Uni-Compartmental Knee Surgery
Uni-compartmental knee replacement surgery utilizes specially designed implants made to resurface one side of the knee joint, and eliminate activity limiting arthritic pain restoring more normal knee function. They are attached to the ends of the femur (thigh bone) and tibia (shin bone), and move on one another during motion.
This surgery is often referred to as “less invasive” or “minimally invasive” because the procedure requires a smaller incision compared to a total knee replacement. The procedure also removes less bone and retains more of the supporting soft tissue than a total knee replacement. The existing ligaments and muscles are maintained for stability and movement of the knee. By resurfacing the arthritic bones, your arthritis pain may be reduced, allowing you to regain a more normal level of activity. Uni-compartmental knee replacement, also called partial knee replacement, may restore your knee joint’s natural range of motion, reduce pain and stiffness.
After you have been prepared for surgery and given an anesthetic, your knee will be cleaned with a solution to sterilize the skin around the entire knee and sterile drapes will be applied to isolate your leg from the rest of your body. An incision will be made over the side of the knee where the arthritis is located. Once the knee joint is visible, the surgeon will bend and straighten your knee and check the surfaces of the bones, the ligaments, the cartilage and other structures to assess the damage to the joint. Following this assessment, your surgeon will proceed in resurfacing the arthritis or diseased knee compartment.
The surgeon will remove the worn out and damaged cartilage surfaces of the shin bone (tibia) and thigh bone (femur) at the knee joint, including small segments of bone necessary for anchoring the implants. The surgeon will use surgical instruments to remove the proper amount of bone from the tibia and femur and to assure the correct alignment of the artificial implants.
The tibial and femoral implants are inserted covering the areas where the arthritic bone has been removed. These components will be secured to the ends of the bones with a caulk-like material known as bone cement.
After the knee has been resurfaced, your surgeon will check the alignment of the implants and verify the knee joint’s range of motion by bending and straightening your leg. The layers of tissues covering you knee are then carefully repaired. The incision is closed with removable or absorbable stitches and a large bandage is applied to your knee. You will be taken off the anesthesia medication and moved to the recovery room. Partial knee replacement surgery usually takes one to two hours. You should plan to remain in the hospital for one or two days after surgery depending on your surgeon’s advice.
Recovery and Rehabilitation
Checking on Your Knee Replacement
Sometimes these knee replacement implants can wear out. Being aware of the warning signs can alert you to see your surgeon as soon as possible.
Why Does an Implant Wear Out?
- An implant can become loose
- An infection can develop near the implant
- The bone can wear away
- The implant can wear down
- Cement that bonds the implant to the bone can crack
- Fractures can occur in your thighbone, the shinbone or the implant itself
Any of the following warning signs may indicate that your knee implant is wearing out:
- Pain reoccurs in the knee or hip area after it has been without much discomfort
- Walking becomes painful in the knee
- Your knee joint becomes stiff and hard to bend and straighten
- Redness and swelling appear at and around the knee joint
- The skin over the knee joint is warm to the touch
- There is a change in the appearance or alignment of the knee
If you have concerns about your knee replacement, contact your physician right away. After your surgeon examines your knee, he or she may want you to have an X-ray or CT scan to assess your condition. Your surgeon will then be able to talk to you about the available treatment options.
Following Knee Replacement Surgery
While You Are in the Hospital
Range of Motion Exercises: The physical therapist will schedule your first inpatient visit shortly after surgery. Treatment will address the range of motion in the knee. Gentle movement will be used to begin to help you regain both the bending and straightening of the knee. If you are using a continuous passive motion (CPM) machine, it will be checked for alignment and settings. Next, you’ll go over your exercise regimen. When you are stabilized, your therapist will assist you during a short outing using your crutches or your walker. Treatment will proceed on a one to two time per day basis. You’ll be on your way home when you can demonstrate a safe ability to get in and out of bed, walk up to 75 feet with your crutches or walker, get up and down flight of stairs and access the bathroom. It is also important that you regain a good muscle contraction of the upper thigh muscle (quadriceps) and that you gain improved knee range of motion.
After You Leave the Hospital
Home Health Needs: Once discharged from the hospital, your therapist will likely see you for in-home treatment. This is to ensure you are safe in and about the home. You should be seen for at least one visit for the safety check and to review your exercise program. In some cases, you may require up to three visits at home before beginning outpatient physical therapy.
As You Progress
Outpatient progression: Your therapist may choose one or more modalities such as heat, ice, or electrical stimulation to help reduce persistent swelling or pain. Continue to use your walker or crutches. If you had a cemented procedure, you’ll advance the weight you place through your sore leg as much as you feel comfortable. If yours was a noncemented procedure, place only the toes down until you’ve had a follow-up x-ray and your doctor or therapist directs you to advance the amount of weight through your leg (usually by the 5th or 6th week postoperatively). Range of motion exercises and techniques will be used to help you regain full bending and straightening of the knee.
An exercise program will be developed, including strengthening, balance, endurance, and functional activities. Your strengthening program will address key muscle groups, including the buttock and hips, thigh and calf muscles. When you are safely putting full weight through the leg, several balance exercises can be chosen to further stabilize and control the knee. Endurance can be achieved through stationary biking, lap swimming, and using an upper body ergometer (upper cycle). Finally, a select group of exercises can be used to simulate day-to-day activities, like going up and down steps, squatting, raising up on your toes, and bending down. Specific exercises may then be chosen to simulate work or hobby demands.
Joint Replacement Patients Should Take Precautions Before Dental Work
What do your joints have to do with your teeth? Quite a bit, if you have a joint replacement. Patients with joint replacements should be sure to mention their new joint replacement to their dentist before undergoing any procedures.
Why? Because certain dental procedures could cause bacteria found in the mouth to travel through the bloodstream and settle in your artificial joint. This increases your risk of contracting an infection, according to the American Dental Association (“Receiving antibiotics before dental treatment. JADA, Nov 2003).
“Any time you work in the mouth, there is a possibility of bleeding, said Matthew L. Creech, DDS, of Fort Wayne Dental Group in Indiana. ? If bleeding occurs, germs can enter the bloodstream and travel to the newly replaced joint area,? Dr. Creech said.
Dental procedures carrying a higher risk of bleeding or producing high levels of bacteria in the blood include tooth extraction, periodontal treatment, dental implant placement, some root canal work, initial placement of orthodontic bands, certain specialized local anesthetic injections, and regular dental cleanings, if bleeding is anticipated.
Preventative antibiotics can be prescribed for you to help decrease the chances of getting an infection after your dental work. ? Pre-medication with an antibiotic is recommended for a period of time after a joint replacement,” Dr. Creech said. The American Dental Association and the American Academy of Orthopedic Surgeons agree that for the first two years after a joint replacement, you may need antibiotic therapy for dental procedures. After that, only high-risk patients may require antibiotics for certain dental treatments.
According to the American Academy of Orthopedic Surgeons, you should also get preventive antibiotics before dental procedures if:
- You have an inflammatory type of arthritis such as rheumatoid arthritis or systemic lupus erythematosis
- Your immune system has been weakened by disease, radiation or drugs
- You have insulin-dependent (Type I) diabetes
- You are undernourished or malnourished
- You have hemophilia
Also, be sure to talk with your dentist about any new or different medicine you may have started taking since your last dentist appointment.
Physical Therapy After Knee Surgery
Activity Immediately Following Surgery
The amount of weight you can put through your knee after surgery will depend on your doctor and the procedure itself. If a cemented procedure was performed, your doctor may approve for you to place a comfortable amount of weight through your operated leg after surgery using your walking aid. If the surgery was done without cement, you may be directed to limit the amount of weight through the operated leg to only a “toe touch” amount of weight for four to six weeks after surgery. There are different ways to surgically reconstruct knees, so the instructions you are to follow after surgery will depend on your doctor and the way the surgery was done.
Precautions: Follow your instructions for the amount of weight you can put through your operated knee. Avoid activities that put a strain on the surgical area. During your activities, let pain guide your decisions. If you feel pain with any activity, stop or alter what you are doing because pain at this stage is an indicator of strain or irritation.
Exercises: Any exercises you do should be done only by the direction of your doctor or therapist. The choices of exercise used after surgery will be gauged by the type of procedure used. You may be given a few exercises that you can do for your ankle and foot. Gently bending and straightening your ankle can keep your calf muscle flexible while “pumping” away excess swelling. Some exercises are used to help control pain and help with movement in the knee. Low grade exercises for the thigh muscles can usually begin right away. Extra pain felt after these or other exercises gives an idea if you are overdoing it. You may need to change the number of repetitions, the amount of pressure, or the how often you are doing the exercises.
Inpatient Physical Therapy
Some doctors will put your knee in a machine right after surgery that slowly and gently bends and straightens your knee. This is called continuous passive motion or CPM. It is often used along with a form of cold treatment that may include a flow of cold water that circulates through hoses and pads around your knee.
Your physical therapist may schedule to see you in the hospital on the same or next day after surgery. The first visit gives your PT an idea of how well your knee is moving, how well you can move in bed, your safety when getting up and sitting on the edge of the bed, and whether you can begin to walk using a walking aid and putting the right amount of weight through your foot. As you gain more confidence and endurance with walking, your therapist will begin to train you how to go up and down stairs using your walking aid.
You may also begin doing a few exercises in your hospital room during the first visit. Gentle range of motion exercises can be used to help begin to restore knee movement. You could begin a series of strengthening exercises for the thigh and leg muscles too. As your condition improves, you may be transported by wheelchair to the physical therapy gym for your treatment sessions.
While you are an inpatient, your therapist may see you for therapy up to two times each day. You can expect to stay in the hospital at least three to four days after surgery. You may be released to go home when you can get in and out of bed safely, walk with the right amount of weight on your foot using a walking aid, go up and down stairs safely, and do your exercises by yourself.
After You Leave the Hospital
Once discharged from the hospital, you may be seen in the home for treatment. This is to make sure you are safe in and around your home. You could be seen for at least one home visit for the safety check and to review your exercise program.
Outpatient Physical Therapy
On your first outpatient visit, your physical therapist will want to gather some more information about the history of your condition. You may be given a questionnaire that helps you tell about the day-to-day problems you are having because of your condition. The information you give will help measure the success of your treatment. You may also be asked to rate your pain on a scale of one to ten. This will help your therapist gauge how much pain you have now and how your pain and symptoms change once you’ve had treatment. Your therapist will probably ask some more questions about your condition to get an idea how your knee has been feeling since your surgery:
- How is your knee feeling since the surgery?
- Where do you feel your pain now?
- Do you have any popping or clicking in the knee?
- Are you getting any more swelling?
Physical therapy Evaluation
Once all this information has been gathered, your condition will be evaluated. The main parts of the evaluation are listed below and may be done in the order chosen by your therapist.
Posture/observation: Your physical therapist will check your overall posture, including the alignment of your low back, pelvis, and your knees and ankles. These have a significant role in the health of your knee. Your therapist will also check the surgical area to make sure the incisions are healing. By comparing each side, your therapist can determine if there is extra swelling, bruising, or a loss in the size of your muscles.
Gait analysis: By watching you walk back and forth, your therapist can make sure your walking aid is adjusted for you and that you are using it safely. The amount of weight you put through your leg will depend on your doctor and the type of procedure done (cemented or not).
Range of motion (ROM): Your therapist will check the ROM in your knee. This is a measurement of how far you can move your knee forward and back (flexion/extension). You may have pain and limited movement in both directions. Movement of the knee cap (patella) is also checked to see that it is moving freely. Your ROM is written down to compare how much improvement you are making with the treatments.
Strength: Your therapist will test the strength of your muscles. You could be asked to hold against resistance as your therapist tests the muscles around the knee. Other muscles that may be checked include the hip, buttocks, and calf muscles. These measurements are compared to your other side. Weakness in key muscles will be addressed with a strengthening program.
Girth: Using a tape measure, your therapist may compare the circumference of your thigh, knee, and calf. This can give an indication of swelling or whether your muscles have lost size (atrophied) from a lack of use or from having pain.
Manual examination: You may be given a manual examination of the knee. Your therapist will carefully move your leg in different positions to make sure that the knee and other joints are moving smoothly. Your therapist will also look at the flexibility of the muscles and tendons around your knee. This type of exam can help guide your therapist to know which type of treatments will help you the most.
Palpation: Palpation is when your therapist feels the soft tissues around the sore area. This is done to check the skin for changes in temperature, to see how much swelling you have, to pin-point areas of soreness, and to see if there are tender points or spasm in the muscles around the knee joints. This can help your therapist get a good idea about which treatments will help you the most.
Treatment Plan: Once the examination is done, your therapist will put together a treatment plan. The treatment plan lists the types of treatments that will be used for your condition. It gives an indication of how many visits you will need and how long you may need therapy. The plan also lists the goals that you and your therapist think will be the most helpful for getting your activities done safely and with the least amount of soreness. Finally, it will include a prognosis, which is how your therapist feels the treatment will help you improve.
Using Physical Therapy to Ease Pain
Your therapist may choose from one or more of the following tools, or modalities, to help control the symptoms you may have from your knee surgery.
Rest: Rest is an important part of treatment after surgery. If you are having pain with an activity or movement, it should be a signal that there is still irritation going on. You should try to avoid all movements and activities that increase your pain. Be sure to use your crutches as assigned by your doctor, and put only the amount of weight on your leg as approved by your doctor.
Ice: Ice makes the blood vessels in the sore area become more narrow, called vasoconstriction. This helps control inflammation that is causing pain and can easily be done as part of a home program. Some ways to put ice on include cold packs, ice bags, or ice massage. Cold packs or ice bags are generally put on the sore area for 10 to 15 minutes.
Heat: Heat makes blood vessels get larger, which is called vasodilation. This action helps to flush away chemicals that are making your knee hurt. It also helps to bring in nutrients and oxygen which help the area heal. True heat in the form of a moist hot pack, a heating pad, or warm shower or bath is more beneficial than creams that merely give the feeling of heat. Hot packs are usually placed on the sore area for 15 to 20 minutes. Special care must be taken to make sure your skin doesn’t overheat and burn. It’s also not a good idea to sleep with an electric hot pad at night.
Swelling control: Massage, cold whirlpool treatment, or compression therapy may be used to control swelling by flushing the extra fluid away from the area. The use of cold, compression, and elevation are a beneficial combination for reducing swelling.
Electrical stimulation: This treatment stimulates nerves by sending an electrical current gently through your skin. In the acute treatment after meniscal surgery, the stimulation can ease pain and help remove swelling. It is often used in combination with ice in the early stages and heat in the later stages of recovery. This treatment stimulates nerves by sending an electrical current gently through your skin. Some people say it feels like a massage on their skin. Electrical stimulation can ease pain by sending impulses that are felt instead of pain. Once the pain eases, muscles that are in spasm begin to relax, letting you move and exercise with less discomfort.
Improving range of motion (ROM): To improve your ROM, your therapist can use graded joint mobilization, manual stretching, and select exercises. The swelling and irritation from a knee surgery can cause movement problems in the knee cap. Getting your knee cap moving will help with your overall knee ROM. Active movement and stretching as part of a home program can also help restore movement.
Gait Training: Once you are safe to put full weight through your operated leg, your therapist will work with you to “fine tune” your gait. Retraining may be needed if you’ve developed a limp, which may be due to apprehension of pain or simply from a habit you’ve developed since your injury or surgery. Getting a normal walking pattern starts with shifting your weight when you walk. If you can visualize the way competitive speed skaters sway their hips when they skate, you’ll get the picture of what it means to shift your weight. When you place your sore-side foot down and prepare to step through with the opposite foot, you may be hesitant to shift the weight of your hip over your planted foot. This leads to an antalic gait–better known as a limp. Practicing this part of the walking cycle may be all that is needed to help you “remember” how to walk without a limp. Your therapist will also make sure that your steps are equal in width and length.
Aquatic therapy: By doing exercise in a pool, the properties of buoyancy and warmth let you exercise with ease of movement. The buoyancy of the pool can be used to make exercise easier, to give resistance with some of the exercise, and to help you begin walking with less stress on your new knee. The warmth can help muscles relax, improve circulation, and ease soreness; letting you move easier. If your therapist works with you in the pool, a few visits are usually all that is needed before you get into a regular program on land. If you are getting good benefits in the pool, you will probably want to get a membership to the pool so your other visits can be used to work on strengthening, walking, and getting you back to doing the activities you enjoy.
Strengthening and Exercise
After a knee surgery, you can expect that your leg muscles will be weak. When muscles weaken from pain or disuse, other muscles overpower the weaker ones. This leads to an imbalance where the weaker muscles become longer and the stronger muscles become shorter. These imbalances change the way the joints usually work. The swelling and pain from your knee pain and surgery can lead to weakened muscles around the knee. The quadriceps muscle usually is affected. Exercises can be chosen to help regain the strength in the muscles around the knee.
Biofeedback: Muscle control is the basis for strength. Using biofeedback can help you get back the contol of the quadriceps muscle. The biofeedback unit has surface electrodes that are put on the skin over the muscle that needs help. As you practice working the muscle, the machine will give you “feedback” to let you see and hear how the weak muscle is performing. The biofeedback unit can also be set to alert you if other muscles are overpowering the weak muscle. Biofeedback can be used while you do your exercise program so you’ll know if you’re actually working the right muscle.
Functional Electrical Stimulation (FES): This is a way to use electrical stimulation to help retrain a weakened or deconditioned muscle. Electrodes are placed over the muscle that is to be retrained. The electrical current passes through the skin and stimulates the motor nerve of the muscle causing it to tighten for a set time without your conscious effort. The machine is usually set to go on for about 10 to 15 seconds and then off for 15 to 30 seconds. Once you get the idea of how the muscle feels when it tightens, you can begin tightening the muscle when the current comes on again. After you get a good contraction going, you should be able to sucessfully tighten the muscle without the use of the current.
Progressive Resistive Exercises (PREs): Many choices of PREs are now used in rehabilitation. Some of these choices include pulley systems, free weights, rubber tubing, manual resistance, and computerized exercise devices. Using PREs is a way to apply graded resistance to muscle groups to gradually help them gain endurance and strength. These exercises typically start with lighter weights with lots of repetitions, and as endurance increases, more weight is gradually used with fewer repetitions.
Exercise Precautions: First, avoid “overdoing” it. If you find that your knee swells up late in the day, it may be a sign you may doing too much too quickly. Second, avoid pain. Pain is an indicator that something isn’t right. You may feel some discomfort with your exercises, but this should be “reasonable” discomfort. If pain is excessive or lasts more than one hour after exercise, inform your therapist at your next visit. You may need to change the number of repetitions, the amount of pressure, or the how often you are doing the exercises.
Progressive Exercise: Exercises will be given to help improve motion, strength, and endurance in the knee. Your program will also address key muscle groups of the buttocks, thigh, and calf. Other exercises can be used to simulate day-to-day activities like stair climbing, pivoting, and squatting, depending on which phase you have completed. Following are some types of exercises that may be used to help your condition.
Closed Kinetic Chain (CKC) Exercises: These are exercises in which the foot is kept on the ground while movement and resistance take place in the joints and muscles above. These types of exercises are important because they are so much like the activities we do every day. For example, a partial squat exercise is the same action as lowering yourself onto a chair or couch. A leg press is a lot like the action of going up a stair or step. These exercises add strength and stability around the muscles and joints of the hip and leg.
Proprioceptive Exercises: These are exercises that help retrain your position sense, also called “joint sense.” If you close your eyes and hold up your hand, you know what your hand is doing, even though you don’t “see” it. We get position sense by way of our vision, middle ear balance, and from tiny receptors in the ligaments and joints. When we close our eyes, we rely on middle ear balance and these special receptors to keep us upright. If there has been swelling or injury in or around a joint, these tiny receptors get injured and do not recover. You can do certain exercises to get the other receptors to do more, regaining what was lost with the damaged receptors. The loss of position sense puts the joint at further risk of injury because the joint loses stability, like having loose lug nuts on a wheel of a car. Special exercises, called proprioceptive or neuromuscular exercises, help protect the knee by “tightening the lug nuts.” You can think of these exercises like balance training. Examples include balancing on one leg with your eyes open/closed, walking on uneven or soft surfaces, or practicing on a special balance board. Some therapists use special manual exercises to get the other receptors working better.
As your condition keeps getting better, you will be given advanced exercises to do at home or in a gym setting. You will recheck with your therapist at regular intervals to make sure you are doing these exercises routinely and safely. During these rechecks, you may be given additional exercises to work on over the next few weeks. Eventually you will be progressed to a final home program. Once you’ve been released to full activity, you may be instructed to follow up with a few visits over the next few months. This will give a comparison of strength and function of the operated knee and to make sure you are performing at peak levels. Before you are completely done with therapy, more measurements will be taken to see how well you’re doing now compared to when you first started in therapy.
Potential Complications Following Knee Replacement Surgery
As with all major surgical procedures, complications can occur. some of the most common complications following knee replacement are thrombophlebitis, infection, stiffness and loosening. This is not intended to be complete list of the possible complications, but these are the most common complications.
Thrombophlebitis, sometimes called Deep Venous Thrombosis (DVT), can occur after any operation, but is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when the blood in the large veins of the leg forms blood clots within the veins. This may cause the leg to swell and become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they get lodged in the capillaries of the lung and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary = lung, embolism = fragment of something traveling through the vascular system). Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible! Some of the commonly used preventative measures include pressure stockings to keep the blood in the legs moving and taking medications that thin the blood and prevent blood clots from forming.
Infection can be a very serious complication following an artificial joint replacement surgery. The chance of getting an infection following artificial knee replacement is probably somewhere around 1%. Some infections may show up very early – before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artificial joint from other infected areas. Your surgeon may want to make sure that you take antibiotics when you have dental work or surgical procedures on your bladder and colon to reduce the risk of spreading germs to the joint.
In some cases, the ability to bend the knee does not return to normal after an artificial knee replacement. Many orthopedic surgeons are now using a machine known as a CPM machine (continuous passive motion) immediately after surgery to try and increase the range of motion following artificial knee replacement. Other orthopedic surgeons rely on physical therapy beginning immediately after the surgery to regain the motion. It is not clear which is the best approach. Both approaches have benefits and risks, and the choice is usually made by the surgeon based on his experience and preferences. To be able to use the leg effectively to rise from a chair, the knee must bend at least to 90 degrees. A desirable range of motion should be greater than 110 degrees. Balancing the ligaments and soft tissues (during surgery) is the most important determining factor in regaining an adequate range of motion following knee replacement, but sometimes increasing scarring after surgery can lead to an increasingly stiff knee. If this occurs, your surgeon may recommend taking you back to the operating room, placing you under anesthesia once again, and forcefully manipulating the knee to regain motion. Basically, this allows the surgeon to breakup and stretch the scar tissue without you feeling it. The goal is to increase the motion in the knee without injuring the joint.
The major reason that artificial joints eventually fail continues to be a process of loosening where the metal or cement meets the bone. There have been great advances in extending how long an artificial joint will last, but all will eventually loosen and require a revision. A loose prosthesis is a problem because it causes pain. Once the pain becomes unbearable, another operation will probably be required to revise the knee replacement.